The present invention relates to tissue expansion devices, and particularly to such expansion devices of the balloon type.
"Tissue expansion" is the term generally used to describe the increase in tissue dimensions under the influence of mechanical forces. This phenomenon occurs naturally in pregnancy, weight gain, tumour growth and the like. It has been applied in various forms for generations, e.g., lip stretching of certain African women and neck stretching of certain Asian women. In 1957, Charles G. Newman, in the publication "The Expansion of an Area of Skin by Progressive Distension of a Subcutaneous Balloon"; Plast. & Reconst. Surg. 19:124, 1957, described the use of this technique to gain skin for an ear reconstruction; this was done by implanting subcutaneously a rubber balloon and progressively inflating it through an external transcutaenous inflatable tube using a three-way stopcock to achieve expansion of the respective area of the skin. In 1976, Radovan, in the publication "Adjacent Flaps Development Using Expandable Silastic Implants", Annual meeting of the American Society of Plastic and Reconstructive Surgeons, Boston, Mass. Sept. 30, 1976, described the use of this method as a means for adjacent flap development. Since then, tissue expansion and tissue expanders have been commonly used in many body areas in a variety of situations and for numerous reasons, e.g., in the preparation of pockets for mammary or other permanent prosthetics.
The tissue expanders commonly used today include an inflatable balloon connected, usually through an inflation tube, to an inflation reservoir having a self-sealing injection-port, all implanted under the skin. The transcutaneous injection port is periodically injected via a hypodermic needle with a quantity of saline fluid in order to inflate the balloon. However, the use of the present subcutaneous self-sealing injection port for inflating the expander may lead to several rather frequent complications, such as erosion of tissues by the hard injection port, leaking from numerous needle punctures with seroma formation and infection, accidental injection into surrounding tissues through the injection port or into its gel-filled double lumen, and difficulty in implanting and removing the reservoir-port.
An object of the present invention is to provide a tissue expansion device having advantages in the above respects.